Wildlanders Birding Database

Understanding Germination

The Art of Growing Native Plants

For many people, being environmentally conscious means growing native plants in their gardens, home landscaping or reclamation on larger properties. Unfortunately, native plant seeds can be difficult to germinate and many people become frustrated with the effort. The purpose of this article is to tell you why they can be difficult. You will be surprised to know that difficult germination actually is of benefit to the plants. And so, we encourage you, please, do not give up. Keep trying. Use the resources on the wildlanders.com website to locate the data you need and join various forums to ask for help. Our native plants, particularly in urban areas, are calling us to discovery their secrets, so that we can bring them back into our lives.

Soil Seed Reserves (SSR)

As our first example, we will discuss soil seed reserves (SSR). But first you need to know what that means.

For any given native plant community, there are seeds mixed in the soil ready to germinate when the time is right for them. We call these seeds a ‘reserve’. In essence, the soil serves as a womb. It helps protect the seeds until the environmental conditions are just right. And thus, we call it a "soil seed reserve". Soils keep moist long after is stops raining acting as a moisture buffer. In addition, buffer both extremes of temperatures shielding the seeds from extreme hot and cold.

Plants many times produce seed infrequently in the wild. Our evergreen trees are a good example of this. We have what are called ‘bumper cone crops’ one year and very few or no cones or seeds the following year. Mother nature works in cycles and it is apparent in the seed production of many of our native plants. The same is true of native grasses, wild flowers, shrubs, vines and deciduous trees. On a good year, we may have no summer drought and the plants respond to the increased summer moisture by producing many, many seeds. But the opposite can happen too. Seed production takes water and food. So in dry years, the adult plants will put all their effort into surviving the drought and produce very little if any seed. Thus, you have cycles of good and bad seed years.

Now mother nature is very complex and there are other environmental factors that come into play. Whether or not a particular insect has a ‘bumper crop’ of young and places stress on the trees is another factor. Insects work in cycles too as do rabbits and deer that may eat the fresh green stems or even the developing leaves. Everything works in cycles. To get a good seed crop, the weather has to be just right, and the ‘predator’ insects and animals have to be low. In addition, the good animals (like pollinating bees) have to be high. All of these and more environmental factors form a very complex environment under which the plants respond with good or bad seed crops.

In any event, seeds are designed to go into dormancy. Native plant seed germination is intentionally very difficult – but for a very good reason! Lets look at one environmental factor (moisture) and assume we have a good seed producing year on year ONE. The summer is relatively cool and moist and we have a bumper crop of seed. The seed falls to the ground in the autumn. We have a high soil seed reserve for the following spring.

The next spring (year 2) let’s assume ALL the seeds germinate. But, the second summer turns out to be hot and dry. The new seedlings have not had enough time to send their roots down deep in the soil and die from the heat and water stress. In addition, the parent plants do not produce any new seed because it is too hot and stressful for them. The result is that there is no seed left in the soil. Because we had 100 percent germination in the spring, the soil seed reserve has been exhausted. There is no seed for year 3.

That is not a good situation and mother nature has designed away to avoid it.

Native seeds are intentionally difficult to germinate so that some are retained and do NOT germinate in the spring of the second year – even when the conditions are perfect. Why? Because mother nature never knows when there is going to be a catastrophic event like a severe drought, a stampede of hungry rabbits (they have cycles too) or even a quick flash wildfire. So some of the seeds remain rather stubborn and waits for two or three springs before germinating. This guarantees there is seed in the soil all the time and that it is never exhausted.

Here is an interesting fact, some species of Ceanothus have seeds that may remain dormant for up to 200 years! On the other extreme is the willows with seed that must remain moist, find a suitable place and begin growing within a week to 10 days or they will begin to die.

When you try to germinate native plants, you will find that many times only a few of the seeds grow. But this is not because the seed is dead. They could be, yes. But in the case of fresh seed, it is likely a result of this natural dormancy that actually ensures the ‘long-term’ survival of the native plants in the wild. It is frustrating for us, but difficult germination is of high value to the plants – they are only trying to survive by insuring a seed reserve for many years.

Cold Stratification

Seeds that you typically purchase at the supermarket or garden shop have been domesticated. They have been selected (over many decades and even centuries) so that they are easy to germinate and grow. But this ‘domestication’ would spell doom for our native plants as explained in the example above.

Here is an another example, consider a common wild flower shedding seed in August. If the seeds grew with the heavy moisture from the first thunderstorm in mid August, the seedlings would soon dry out and die as a result of the next 1-2 weeks of hot weather. Somehow those seeds have to ignore the intermittent summer moisture and get through the winter until the continuous spring rains begin to fall.

My point is, non-native garden seeds from the store are easy to grow because we have taken away their ability to survive in the wild. While they grow easily, we must care for them and water them to keep them alive. It is a trade off. To support the environment implies that native plants need to be able to take care of themselves. Which is to say we want them to retain their stubborn germination characteristics.

Many native seeds have an inherent chemical process (enzymes) that controls the germination – the ‘germination enzymes’ are activated only after a certain period of cold weather (usually 8-16 weeks). This assures that the first rain in August will not result in germination. The seeds will remain dormant until they receive enough cold to trigger the enzyme and the germination cycle. There is also the opposite situtaion where enzymes inhibit germination and where cold destroys them over time thus releasing the germination. Regardless of the germination principles, they have to go through a cold period. This assures that they stay dormant during the hot summer period and endure as seeds until the spring.

We call this process of "requiring cold to germainate" by a rather funny term: stratification. A requirement of 12 weeks of cold weather assures that the plants will endure as seeds until the spring – when water is plentiful and the seedling can survive.

Warm Stratification

So now we have looked at two germination requirements. A rather stubbornness of germination and cold stratification. But there are others. Some plants require warm stratification (a period of hot weather to trigger the enzymes) – most common in plants that have evolved to grow in the fall so that they are partly grown by the following spring. As a partly grown plant, they are more able to take advantage of the spring moisture and optimum growing conditions. The fall germination of some plants gives them a ‘head start’ the following spring.

Other Germination Requirements

Some plants require fire. Certain varieties of lodgepole pine cones are sealed in sap or resin (serotenous cones). The seeds will not be released until a quick ground fire comes through and melts the sap - the cones pop open and the seeds are then released AFTER the fire when they are needed most. Again, it is a survival mechanism as the cones serve as an insulation layer around the seeds during the actual fire period.

And so, each plant has its unique way of dealing with survival. Some seeds need both a cold and a warm stratification. If you plant them in the spring, even after keeping them in the refrigerator for 12 weeks, they will not grow. Why? It may very likely be that they may need a warm stratification before the cold stratification. Even within a species, you can find differences in the germination requirements. For example, the lodgepole pine of the west slope of the cascades does NOT require fire to open the cones.

And then there is acid treatment to simulate digestion. The consumption of seeds can break dormancy via the digestive systems of birds and mammals. Some seeds require acid treatment (stomach acids) to dissolve the seed coat so that water can get into the embryo. The seeds have designed a method that requires consumption by birds – which both digest part of the seed coat but also carry the seed long distances to where it might be needed most. Other seeds require scarification in the form of grinding soils from hoof or foot traffic. The lupines are a good example of this. For some plants, this may be an adaptation to stimulate germination only after the parent plants have been consumed (and trampled) by large ungulates.

All of this makes for very difficult germination from the human perspective. Growing native seeds is both an art and a science. And while folks can give you suggestions, it is like raising your own child, until you raise your own you will not really know what it is all about.

Native plants are not easy to grow. And if you are successful, you can take credit for that! It is a great accomplishment. The greater the challenge, the greater the reward. Any parent will tell you that. So please don’t throw those seeds away until you have tried several times and several methods to break their dormancy.

One further note, the stubbornness of seeds can be such that you will have no germination. The next year you plant another type of seed and, low and behold, the old seed from two years ago comes up all over the place! Some plants just require several years before they begin to grow. In any event, there are many, many factors that control germination. Multiple freeze-thaw cycles, chemicals from soot and smoke that trigger enzymes, etc. We must strive to both preserve our native plants as well as their stubbornness. In that way, we assure their survival in both the short and the long term. We support both our current environment and the sustainability of that environment. So please, do not give up. By enduring the stubbornness of native plant seeds, we are supporting a sustainable ecology.

Be cool, be green, be seen… be a Wildlander.

Wildlanders.com!
Please note that we have two pricing models for our seeds. The first is $1.95 per packet with a money back guarantee. The second is 95 cents a pack with no guarantee. We provide two pricing models to encourage new folks to try growing native seeds with the understanding that you can get your money back. If you are successful, you will try again – and we just helped give birth to a new native plant supporter! Alternatively, more experienced folks are more successful with their growing techniques and are more able to take advantage of the savings at 95 cents per packet.

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